CBP and p300 are proteins identified through protein interaction assays. CBP binds to the transcription factor CREB, while p300 interacts with the adenoviral-transforming protein E1A. Both proteins have highly conserved sequences and are involved in various cellular functions, including cell growth, transformation, and development. This review focuses on the role of CBP and p300 in these processes. CBP and p300 have dual roles in cell growth and transformation. They can act as tumor suppressors and are essential for the actions of many oncogenes. CBP and p300 are involved in tumor suppression, as evidenced by studies showing that mice with a null mutation in one CBP allele develop hematological abnormalities and a high incidence of hematological malignancies. These findings suggest that CBP is a tumor suppressor, while p300's role in humans is less clear. CBP and p300 also interact with the tumor suppressor p53, which is involved in DNA damage response. p53 can be acetylated by p300, which enhances its DNA binding and transcriptional activation. This interaction is crucial for p53-mediated gene expression and cell cycle regulation. CBP and p300 also contribute to the regulation of p53 degradation. For example, the adenovirus E1A blocks p53's ability to induce its target genes, such as mdm2, which is involved in p53 degradation. The interaction between p53 and p300 is essential for p53 turnover. Additionally, CBP and p300 are involved in the regulation of other tumor suppressors, such as BRCA-1, which is involved in genomic integrity and DNA damage response. Chromosomal translocations involving CBP/p300 are associated with various leukemias. For example, the t(8;16)(p11;p13) translocation fuses the MOZ gene onto the CBP gene, leading to transformation. Similarly, the t(11;16)(q23;p13.3) translocation fuses the MLL gene with the CBP gene, contributing to leukemia. These translocations highlight the role of CBP/p300 in cell transformation. CBP/p300 also interact with viral oncoproteins. For example, the adenovirus E1A protein interacts with CBP/p300 and blocks its coactivator functions. Similarly, the SV40 T-antigen interacts with CBP/p300 and is involved in cell transformation. The human papillomavirus E6 protein interacts with CBP/p300 and contributes to p53 degradation, leading to cell transformation. CBP/p300 are also involved in the regulation of cellular oncogenes. For example, the APCBP and p300 are proteins identified through protein interaction assays. CBP binds to the transcription factor CREB, while p300 interacts with the adenoviral-transforming protein E1A. Both proteins have highly conserved sequences and are involved in various cellular functions, including cell growth, transformation, and development. This review focuses on the role of CBP and p300 in these processes. CBP and p300 have dual roles in cell growth and transformation. They can act as tumor suppressors and are essential for the actions of many oncogenes. CBP and p300 are involved in tumor suppression, as evidenced by studies showing that mice with a null mutation in one CBP allele develop hematological abnormalities and a high incidence of hematological malignancies. These findings suggest that CBP is a tumor suppressor, while p300's role in humans is less clear. CBP and p300 also interact with the tumor suppressor p53, which is involved in DNA damage response. p53 can be acetylated by p300, which enhances its DNA binding and transcriptional activation. This interaction is crucial for p53-mediated gene expression and cell cycle regulation. CBP and p300 also contribute to the regulation of p53 degradation. For example, the adenovirus E1A blocks p53's ability to induce its target genes, such as mdm2, which is involved in p53 degradation. The interaction between p53 and p300 is essential for p53 turnover. Additionally, CBP and p300 are involved in the regulation of other tumor suppressors, such as BRCA-1, which is involved in genomic integrity and DNA damage response. Chromosomal translocations involving CBP/p300 are associated with various leukemias. For example, the t(8;16)(p11;p13) translocation fuses the MOZ gene onto the CBP gene, leading to transformation. Similarly, the t(11;16)(q23;p13.3) translocation fuses the MLL gene with the CBP gene, contributing to leukemia. These translocations highlight the role of CBP/p300 in cell transformation. CBP/p300 also interact with viral oncoproteins. For example, the adenovirus E1A protein interacts with CBP/p300 and blocks its coactivator functions. Similarly, the SV40 T-antigen interacts with CBP/p300 and is involved in cell transformation. The human papillomavirus E6 protein interacts with CBP/p300 and contributes to p53 degradation, leading to cell transformation. CBP/p300 are also involved in the regulation of cellular oncogenes. For example, the AP